An information processing model for the development of decision making will be formulated and tested. The model stresses the contingency of decision making strategies on the structure of the decision task. Given a complex task, decision makers will simplify it by using less of the relevant information that is available in the environment. Older children and adults, however, are expected to employ more complex strategies using more of the relevant information than younger children. The information used in decision making by 7-year-olds, 10-year-olds, and college students will be assessed by requiring them to make decisions between pairs of alternatives having random outcomes leading to losses and gains. A within subject factorial design varying gains, losses, and probabilities will be used to assess the sensitivity of each subject to these dimensions of information. In a second study, similar groups of subjects will make decisions in both simple (2 alternative) and complex (4 alternative) tasks to assess the effect of task complexity on decision making strategy.